CHAPTER IV. 



DISEASES OF BLOOD-VESSELS. 



Diseases of vessels, arteries or veins, in animals of the bovine and 

 ovine species are frequently nothing more than localisations of grave 

 general disorders, and rarely admit of treatment. This is specially the 

 case in regard to arteries, but a study of the diseases of veins has some 

 practical importance. 



PHLEBITIS. 



Phlebitis, i.e., inflammation of a vein, is of interest only in the case 

 of bovine animals. In them certain conditions may occur which the 

 practitioner should understand, with a vie^Y either to prevention or treat- 

 ment. Inflammation of the veins may be due to external causes, such as 

 surgical or accidental wounds (phlebotomy wounds, accidental wounds, 

 local inflammations, etc.), or to internal causes of infectious origin 

 (general infection, puerperal infection, etc.). 



ACCIDENTAL PHLEBITIS. 



The jugular vein may become inflamed as a result of accidental 

 wounds or of phlebotomy, but the mammary vein in cows is much more 

 frequently affected. In both cases the disease is due to infection of the 

 clot which seals the vessel ; it may assume the form of either adhesive 

 phlebitis or suppurative phlebitis. Whether produced directly by the use 

 of infected instruments or whether it is of a secondary character, trace- 

 able to the clot being infected by germs entering from without being 

 conveyed to the wounds by the head-stall chains, by litter, manure, etc., 

 the result is the same. The inflauunation, at first confined to the 

 endothelium, extends to the wall of the vein and causes fibrin to be 

 precipitated over the inner wall of the inflamed vein for a distance 

 varying with each case. 



If the micro-organisms do not produce suppuration, the vein appears 

 simply thrombosed and inflamed, the phlebitis remains of an adhesive 

 character, and may disappear spontaneously, provided the animal be kept 

 ({uiet. If, on the other hand, suppuration is set up, the clot gradually 

 breaks down, the internal surface of the vein develops granulations and 



